GST scares a lot of first-time online sellers into either ignoring it or over-paying a consultant to explain the basics. Neither is necessary. This guide breaks down what GST actually means for an Indian D2C, Instagram or WhatsApp seller in 2026 — when you must register, how the tax is structured, how to invoice correctly, and how to file — in plain language. (One honest caveat up front: this is a practical explainer, not tax advice. Rules change and edge cases are real, so confirm your specifics with a qualified CA before you act.)
Do you actually need GST registration?
This is the first question, and the answer is "it depends on how you sell."
You are generally required to register when any of these apply:
- Your annual turnover crosses ₹40 lakh for goods or ₹20 lakh for services (in special-category states, ₹20 lakh and ₹10 lakh).
- You sell inter-state — shipping goods to customers in other states.
- You sell through an e-commerce operator / marketplace (Amazon, Flipkart, Meesho, etc.). These platforms typically require a GSTIN before you can list.
So a baker selling cakes only within Pune under ₹40 lakh may not need GST yet. But the moment they ship to Mumbai — no, that's the same state — say they ship to Ahmedabad (Gujarat), or list on a marketplace, registration kicks in.
Even when you're not strictly required, many sellers register early. A GSTIN lets you claim input tax credit on your purchases (raw materials, packaging, ads, platform fees) and issue proper tax invoices, which B2B buyers and serious customers expect. If you're building a real brand, register sooner rather than later. Our guide to starting an online store in India covers where this fits in the overall launch.
GSTIN basics
Once registered, you get a GSTIN — a 15-character identifier. It's structured, not random:
- First 2 digits — your state code (e.g. 27 for Maharashtra, 29 for Karnataka).
- Next 10 characters — your PAN.
- 13th digit — entity number for that PAN in the state.
- 14th — the letter Z (default).
- 15th — a checksum character.
Your GSTIN must appear on every tax invoice you issue and on your store. Registration is free on the official GST portal; you'll need PAN, Aadhaar, a bank account, and proof of business address.
HSN codes: classifying what you sell
Every product is classified under an HSN code (Harmonised System of Nomenclature) that determines its GST rate. Services use SAC codes.
How many digits you must quote depends on turnover:
- Up to ₹5 crore — 4-digit HSN on B2B invoices (optional on B2C, but good practice).
- Above ₹5 crore — 6-digit HSN.
Get your HSN right, because it fixes your tax rate. For example, cotton sarees, ready-made garments, handicrafts and cosmetics all sit in different HSN chapters with different rates. When in doubt, check the official HSN lookup or ask your CA — guessing a wrong code means charging the wrong tax.
The GST slabs: 0, 5, 12, 18 and 28%
India uses five main GST rates. Which one applies depends on your product's HSN:
- 0% (exempt / nil-rated) — unbranded staples, fresh produce, some books.
- 5% — apparel priced under ₹1,000, footwear under a threshold, packaged food staples, small household items.
- 12% — apparel above ₹1,000, processed foods, some electronics accessories.
- 18% — the most common slab for D2C: cosmetics, most electronics, services, many consumer goods.
- 28% — luxury and "sin" goods: aerated drinks, high-end items, etc.
If you sell apparel, note the price-based split (5% under ₹1,000, 12% above) — it's a common source of invoicing errors. To see exactly how a rate breaks down on a given price, run it through the free GST calculator, which shows you both GST-inclusive and GST-exclusive amounts and the tax split.
CGST/SGST vs IGST: the one rule that trips people up
The total GST rate is the same nationwide — but how it splits depends on where the buyer is:
- Intra-state sale (you and the buyer in the same state): the tax splits into CGST + SGST, each half the rate. An 18% item = 9% CGST + 9% SGST.
- Inter-state sale (buyer in a different state): the full rate is charged as IGST. An 18% item = 18% IGST.
The rate the customer pays is identical either way (18%). What changes is which government gets it and how it appears on the invoice. Your store or invoicing tool should decide this automatically from the customer's shipping state — doing it by hand is where mistakes creep in.
Issuing tax invoices correctly
A GST-compliant tax invoice isn't optional once you're registered. Each one must include:
- Your business name, address and GSTIN.
- A unique, sequential invoice number and the date.
- Customer name, address and GSTIN (if they're registered).
- HSN code, description, quantity and taxable value per item.
- The tax split — CGST + SGST, or IGST — with rates and amounts shown separately.
- Place of supply (the state) for inter-state sales.
You don't need expensive software for this. A free GST invoice generator produces compliant invoices in seconds, and a platform like OrderLyne generates them automatically on every order so you're never assembling invoices by hand.
Calculating GST without mistakes
Two everyday calculations trip sellers up:
- Setting an inclusive price. If you want a kurti to sell at ₹999 all-in at 12% GST, you need to back out the base price (₹999 ÷ 1.12 = ₹892) so your margins are right. The GST calculator does this instantly.
- Adding GST to a base price. A ₹500 base item at 18% becomes ₹590 to the customer (₹90 GST).
Decide early whether your listed prices are GST-inclusive (cleaner for B2C) or exclusive, and be consistent across your store.
Filing GSTR-1 and your returns
Registered sellers file returns regularly — the two you'll meet most:
- GSTR-1 — details of your outward sales (invoice-level or summary), filed monthly or quarterly depending on turnover and the QRMP scheme.
- GSTR-3B — a summary return with your tax liability and input credit, filed and paid monthly (or quarterly under QRMP).
The pain here is compiling sales data. If your orders live across WhatsApp chats, a spreadsheet and a marketplace, month-end is a scramble. Platforms with built-in GSTR-1 reports — OrderLyne includes these — export your outward-supply data in the format your CA or the portal expects, turning hours of reconciliation into a download.
TCS on marketplaces
If you sell on marketplaces, you'll see TCS (Tax Collected at Source) deducted. The e-commerce operator collects 0.5% CGST + 0.5% SGST (1% total intra-state, or 1% IGST inter-state) on the net taxable value of your sales and deposits it against your GSTIN, reporting it in their GSTR-8.
This is not an extra tax — it's a prepayment. You reconcile the operator's GSTR-8 with your own records and claim the TCS back as a credit in your electronic cash ledger. The one discipline it demands: keep your marketplace sales data clean so the reconciliation matches. Selling on your own store avoids marketplace TCS entirely, which is one more reason to own your channel — see our take on a free Shopify alternative for India.
The composition scheme: a simpler option for small sellers
If your turnover is modest and you sell mostly within your state, the composition scheme can simplify GST. Instead of charging GST on each invoice and filing detailed returns, eligible traders pay a small flat rate on turnover (1% for traders, higher for others) and file a quarterly statement plus an annual return.
The trade-offs are real, though:
- You cannot collect GST from customers or issue tax invoices — only a bill of supply.
- You cannot claim input tax credit on your purchases.
- You generally cannot sell inter-state, and crucially, you cannot sell through e-commerce operators that collect TCS.
That last point rules the scheme out for most online sellers on marketplaces. But for a small local seller shipping only within their state from their own store, it can cut compliance work sharply. Ask your CA whether you qualify and whether the lost input credit is worth the simplicity.
A quick month-end routine that keeps GST painless
The sellers who dread GST are usually the ones who leave everything to the last day. A light monthly routine fixes that:
- Reconcile sales — make sure every order has a matching tax invoice with the right HSN and tax split.
- Match marketplace TCS — check the operator's GSTR-8 against your records so nothing is missed at credit time.
- Tally input credit — keep invoices for packaging, ads, courier and platform fees; these reduce what you owe.
- Export your GSTR-1 data — a platform with built-in reports turns this into a one-click download instead of a spreadsheet marathon.
Do this on the same date every month and filing becomes a formality rather than a fire drill.
Keep it simple, keep records, ask a CA
GST feels heavier than it is. Register when the rules say you must (inter-state or marketplace selling usually means "now"), classify products with the right HSN, charge the correct slab, split CGST/SGST vs IGST by the buyer's state, issue proper invoices, and keep clean monthly records so filing is a download rather than a scramble.
A platform that generates GST invoices and GSTR-1 reports automatically — like OrderLyne, free to start — removes most of the manual work. For anything specific to your business structure or edge cases, spend an hour with a qualified CA; it's the cheapest insurance you'll buy this year. This guide is practical, not legal advice.